<TileButton>:
    canvas.before:
        Color:
            rgba: self.background_color
        Rectangle:
            pos: self.pos
            size: self.size

<PuzzleBoard>:
    canvas.before:
        Color:
            rgba: 0.2, 0.2, 0.2, 1
        Rectangle:
            pos: self.pos
            size: self.size